This is not simple as it means giving the teacher the "log in as" capability - see http://docs.moodle.org/en/Capabilities/moodle/user:loginas and this has to be done with careful consideration of privacy issues. If it's just a one-off event with one student then the admin or a manager can do this by default.
What I am mostly looking for is a way to submit the quiz for the student after the time has run out so it can be graded by the system and not manually. If there is a way to do this without having to give the teacher the "log in as" capability that would be great.
In the quiz setting, 'When time expires'. Set that to 'Submit attempts automatically'.
You could even turn that on under Admin -> Plugins -> Activity modules -> Quiz, so it is the default for all new quizzes.
Thank you. That seems to be the simple solution I was looking for.
